The overall objective of this research project is to understand how steroid hormones, in conjunction with their receptors, modulate specific gene expression. We have chosen to study the induction of egg white protein synthesis in the chick oviduct in response to estrogen and progesterone because of the relative ease of analysis of early response in this tissue. We are proceeding towards an understanding of the mechanisms involved on three fronts: (a) measuring the kinetics, dose-response relationships, and hormonal interactions in vivo, (b) establishing a tissue explant system that will respond to steroids in vitro, and (c) developing methods for measuring gene activation in isolated nuclei.